Make yourself as 2D as possible... Gee hard task! Fun to do though! Start by putting an awfully standard flower in your hair (you know the ones you drew... ages ago five leaves... easy peasy XD) You could make the costume in grey scale... Start by printing a Kairi picture in Greytones... Then make it that way, bodypaint\schmink yourself white en dye your hair black...

I saw someone planning to do this costume as well, but as fas as I know she wanted to do the first costume just all in greyshades...

In my opinion - look at Soras first costume (from the first game) and his Timeless River outfit and search for the differenzes. Then try to change Kairis first outfit like they did with Soras ^^ And I second that flower idea from lisu-chan XD sounds awefully great

The idea I ended up working with for the costume is off of her 2nd game costume. By looking at Sora's Timeless River bit I think they went with his first one because it was a simpler costume. In light of that, I chose to do her 2nd game costume because it's a simpler and plainer costume.

As for coloring and whatnot, it's pretty much up to you. Just look at the costume and figure out what colors will work the best for your idea. I do like the ide aof the flower. That sounds really cute. I might use that in mine if you don't mind terribly. As for the white arms and legs, for my legs I'm doing white tights and then using a type of cream makeup that dries on the rest of my body.

Oh and for further ideas as for the cut of the costume I looked at the two girl characters in Timeless river. (Yes the cow and the chicken) And I got a few ideas to make it more cartoony-y from them. I hope I helped out a bit. Good luck!

As long as it's black and white and people recognize you as Kairi, they'll put 1 + 1 together! XD I love the fact people love my flower idea, it just popped in my head, and I think I'm doing a timeless river Kairi now as well, or make it a Riku one since I'm tall! XD Sorry ripping cosplay plans here!

BTW I think you should stick with the KH1 Kairi, it'll be I dunno... better! XD